Monitoring and assessment of restoration of a rainforest remnant at Wingham Brush, NSW

Abstract

Wingham Brush is a 9-ha remnant of lowland subtropical rainforest, on mid-north coast New South Wales, Australia, with high floristic diversity (about 200 species, more than 70 endemic trees and 27 endemic vines). A history of disturbance, environmental mismanagement and flooding from the Manning River resulted in many exotic species vigorously invading the rainforest. By the late 1970s weeds blanketed large sections of the forest, preventing regeneration of native species and destroying the canopy . By 1978 rainforest ecologists thought it 'doubtful whether the rainforest could be saved from extinction.' In 1980 a restoration program funded by the National Trust of Australia (NSW), used the Bradley Method of bush regeneration. However, this method did not consider the unique character of the rainforest community, which required the highest priority to be restoring the canopy. The National Herbarium of New South Wales became involved in 1984 as an independent agency to monitor the progress of the regeneration and assess the techniques being used, in particular the use of glyphosate. Monitoring provided evidence of beneficial change, showed how it occurred and has since been used as a basis for planning, documenting and assessing progress in rainforest regeneration. Reformation of the canopy allowed the forest floor to stabilize under a more constant microclimate, encouraging germination of shade-loving rainforest species. Maximum and minimum temperature values demonstrated the buffering effect of the closed rainforest canopy. After 20 years, Wingham Brush has changed from a degraded forest, dominated by exotic vines, with many large gaps in the canopy, to a rainforest with an intact canopy, enlarged core forest area and reduced edge effect, that supports the diversity and structure of a healthy subtropical rainforest. Techniques developed in the 'Wingham Brush Method', have become the basis for restoration programs in other rainforest areas. The principles are: be canopyfocused, be flexible, assess each site individually, and use techniques appropriate to problems encountered and goals of the long-term program.

Assisted natural regeneration accelerates recovery of highly disturbed rainforest

“…Reformation of the canopy has been shown to be an important milestone in forest recovery, allowing for the microclimate on the forest floor to stabilise, in turn improving conditions for the germination and survival of shade‐loving rainforest species (Harden et al . ). The canopy gaps of ungrazed assisted regeneration sites provide sunlight for opportunistic grasses and forbs and increase the likelihood of these in the seed bank (Paul et al .…”

Restoring Rainforest Fragments: Survival of Mixed‐Native Species Seedlings under Contrasting Site Conditions in the Western Ghats, India

“…The importance of controlling smothering weeds and vines through manual weeding or herbicide application has been noted in restoration of many Australian rainforest sites (Goosem & Tucker 1995;Lamb et al 1997;Harden et al 2004). The removal of invasive weeds reduces competition for space, light, and nutrients, improving survival of planted seedlings (Harden et al 2004). -year period (2003-2005) at restoration sites planted in the Injipara rainforest fragment.…”

“…Few tropical forest restoration projects have reported percent survival by site, year, or species (Elliott et al 2003;McDonald et al 2003;Harden et al 2004;Lamb et al 2005). McDonald et al (2003) reported average survival rates of 39 and 49% after 12 months and 21 and 20% after 42 months at ridge-top and valley-bottom locations, respectively, in a tropical montane forest of Jamaica.…”

“…Experience gained from tropical forest restoration projects around the world have shown that rainforest restoration can be influenced by factors such as proximity to seed sources, presence of animal dispersal agents, and degree of control of invasive weeds (Goosem & Tucker 1995;Lamb et al 1997Lamb et al , 2005Holl et al 2000;Elliott et al 2003;McDonald et al 2003;Harden et al 2004). Most rainforest restoration projects have focused on the recovery of trees to reestablish canopy closure which allows the forest floor to stabilize under a more constant microclimate and facilitates germination of shade-loving rainforest species (Harden et al 2004). Earlier studies have suggested planting pioneer species in highly degraded sites, followed by the introduction of mature forest species once the pioneers form a closed-canopy layer (Goosem & Tucker 1995).…”

Biodiversity of Lianas

“…In addition, change in microenvironment, particularly intensity of light penetration might suppress native species regeneration. Canopy branches may break due to the sheer weight of overtopping exotic vines (Harden and Fox 1988 ;Harden et al 2004 ). Some species like Mikania micrantha tend to form dense ground cover carpets, suppressing native fl ora.…”